Double or halve?

From NRICH

Collect resources

You will need:

• 2 different coloured markers or coloured pencils​

• something to write on​

• a blank hundreds chart ​

• a 6-sided dice or a 1-6 spinner.

How to play

• Choose a target number between 10 and 99.

• Write your target number on your blank hundreds chart.

  • Our target number was 27 so we wrote 27 where it would be found on a top-down hundreds chart that starts at one.

• The first player rolls the dice and chooses whether to double or halve the number.

• Record the roll on the game board, by shading the amount of squares.

• Players record the running total to the side of their hundreds chart game board.

• Players take turns to roll the dice.

  • If a player can't go, they miss a turn.

• The winner is the player who reaches the target number exactly.

Discuss/reflect

• If you played the game again are there any moves you would change?

  • Would you choose to halve a number that you doubled? Why or why not?

• Play a game where you can double, halve or keep your roll. Do you think this might make it easier to reach the target number?

  • What if you could only halve the number each time?